As is described in U.S. Pat. No. 5,498,466, an intumescent firestop device is used to prevent fire from spreading from one room to another through an opening or aperture in a wall, floor or ceiling through which a pipe runs. As is there set forth, a conventional firestop device is typically wrapped around a pipe adjacent to the wall, floor or ceiling opening. If a fire then breaks out in the room, the intumescent material within the firestop device is intended to intumesce (i.e., expand) when the temperature reaches a certain level. With the expansion of the intumescent material being directed inward by the outer restraining layer of the firestop device, the result is a crushing of the pipe by the intumescing material--following from a softening of the pipe by the heat of the fire. The end result is described as a closing-off of the opening in the wall with a hard char, which is simultaneously fire resistant, thermal insulating, smoke depressing, and able to withstand the forces exerted by a stream of water from a fire hose.
U.S. Pat. No. 5,498,466 goes further in describing a preferred intumescent composite to produce these results, in which the composite is a moldable, non-curing putty. Also described there is a firestop device (incorporating the intumescent composite), which is installed around a pipe near a wall opening through which the pipe runs, with the intumescent composite exuding into the annular space between the pipe and the wall, floor, or ceiling opening in forming a cold-gas seal.
Experience has shown that such firestop device works quite well where the wall, floor or ceiling is of a concrete construction, where it is necessary only to firestop on one side. As FIG. 2 of that patent illustrates, for example, several screwing attachment tabs secure the device to the wall, floor or ceiling. In the embodiment there described, four attachment tabs are employed, pre-bent away about 90.degree. from the layer of intumescent composite. Although performing quite well, installation of such firestop device entails a certain degree of labor intensiveness in attaching the tabs employed--but offers the further limitation in that when dealing with a gypsum wallboard assembly, for example, the installation needs to be repeated on the other side of the wall as well, thereby repeating the process and adding to its installation cost. Obviously, furthermore, if a construction requires firestopping on both sides of a concrete wall, floor or ceiling, the installation process needs to be duplicated on the opposite side as well, in similarly adding to the overall costs.